Change /etc/default/libvirt-bin to libvirtd

The file has changed as part of the move to the new libvirt package in
the Ubuntu UCA repository.

We need to change this in the task too, otherwise this will fail when
nova_libvirtd_listen_tcp is set to 1.

Change-Id: I0637338a9a6a6f57174295e166819d4ecb2be0ff

tasks/nova_compute_kvm.yml

@@ -64,7 +64,7 @@
 
 - name: Set libvirt runtime options when listening on tcp (Ubuntu)
   lineinfile:
-    dest: "/etc/default/libvirt-bin"
+    dest: "/etc/default/libvirtd"
     line: 'libvirtd_opts="-l"'
     regexp: "^libvirtd_opts="
     backup: "yes"